protected override void OnElementChanged(ElementChangedEventArgs <Slider> e)
        {
            base.OnElementChanged(e);

            formsSlider = (TouchEventSlider)e.NewElement;

            if (Control != null && !areListenersAdded)
            {
                Control.StartTrackingTouch += SeekbarOnStartTrackingTouch;
                Control.StopTrackingTouch  += SeekbarOnStopTrackingTouch;
                areListenersAdded           = true;
            }
        }
        protected override void OnElementChanged(ElementChangedEventArgs <Slider> e)
        {
            base.OnElementChanged(e);

            formsSlider = (TouchEventSlider)e.NewElement;

            if (Control != null)
            {
                Control.TouchDown      += ControlOnTouchDown;
                Control.TouchUpInside  += ControlOnTouchUp;
                Control.TouchUpOutside += ControlOnTouchUp;
            }
        }